Nikorinbō is one of the two komainu, or guardian lion-dog statues, that serve at the impoverished Mangan Shrine in the world of Ojarumaru. He is the younger brother of Okorinbō and is characterized by a perpetually cheerful and smiling demeanor, a contrast to his brother’s more hot-tempered nature. His name reflects this personality, as nikori means a gentle smile. Together with Okorinbō, he constantly devises various get‑rich‑quick schemes and odd jobs in an attempt to collect enough donations to repair and rebuild their dilapidated shrine. Despite their earnest efforts, their plans almost always end in failure.

Within the story, Nikorinbō and his brother appear as recurring supporting characters who interact with the main cast, particularly with the poverty god Binchan. In some episodes, the three form a temporary trio, calling themselves the “Bō‑sans” (Okorinbō, Nikorinbō, and Binbō) and carrying out joint money‑making ventures. Nikorinbō also serves as the founder of the fan club for the Tiny Things Club, a group of small creatures and objects in Moonlight Town, while his brother holds the position of club president. Over the course of the series, Nikorinbō’s optimistic attitude remains consistent, and he occasionally demonstrates the ability to transform into a spinning top or other objects, often as part of the twins’ humorous predicaments. His key relationships are with his brother Okorinbō, with whom he shares a close but bickering bond, and with Binchan, who frequently leads them into dubious partnerships. Although they are not central to the main plot, the komainu twins provide recurring comic relief and highlight themes of perseverance and community.